Switching mechanism



Sept. 13, 1932. w SCOTT, JR 1,877,698

SWITCHING MECHANISM Filed July 12, 1950 3 Sheets-Sheet l A 5 C D 1 N VEN TOR yum #Jwif} BY wwsw ATTORNEY 5 Sheets-Sheet 2 w. M. SCOTT, JR

SWITCHING MECHANISM Filed July 12, 1930 38 (NVENTOR I MI J H ml 14 E2511 ATTORNEY Sept. 13, 1932.

Sept. 13, 1932.

W. M. SCOTT, JR

SWITCHING MECHANISM Filed JuLv 12, 1930 3 Sheets-Sheet 5 BY ATTORNEY Patented Sept. 13, 1932 UNITED STATES PATENT OFFICE WILLIAM H. SCOTT, TB... OF PHILADELPHIA, PENNSYLVANIA, ASBIGNOB TO I-T-ll CIRCUIT BREAKER COHFANY, O1 PHILADELPHIA, PENNSYLVANIA, A CORPORA- T1011 NEW JERSEY swrrcnmo nacxmsx Application filed July HD1930. Serial No. 7,338.

My invention relates to switching mech anismsand particularly to automatic circult breakers for controlling circuits carrying current for power, lighting, or other pur 'poses.

In accordance with myinvention, the contact mechanism of a switch, or circuit breaker, comprises a plurality of contact elements, or groups of elements, connected electr cally in parallel, adapted to be selectively d1sconnected from a common operating structure for independent movement to open circuit position to permit for example, cleaning of a contact or set of contacts without interruption of current through the switch. The total number of contacts, the number of grou s of contacts, and the number of contacts in each group are so proportioned that upon the opening, for necessary periods, of any one group of one or more contacts as above described, the additional load distributed among the other contacts does not cause the current carried by any one of them to exceed a safe value.

More specifically, an operating bar connects the actuating arms of corresponding contacts or groups of contacts, and the relation between the bar and the individual arms is such that when an arm is disconnected from the bar and the switch is in closed circuit position, the disconnected arm can move in a path unobstructed by the bar to effect opening and reclosin of the associated contact independently o the other contacts, and further that when the contacts are in open circuit position, the disconnection of an arm does not permit of independent movement of the corresponding contact element to closed circuit position.

Particularly to avoid the possibility of injury to one cleaning or otherwise working upon the selectively opened contacts, there is provided means for positively maintaining the remaining portion of the switch in closed circuit position regardless of accidental movement, shock, jar or the occurrence of any abnormal electrical condition as overload, under voltage; etc.

My invention further resides in the features of construction and arrangement hereinafter described and claimed.

For an understanding of my invention, reference is to be had to the accompanying drawings in which: 7

Fig. 1 illustrates in front elevation a multisection electro-mecha'nically operated single pole circuit breaker.

Fig. 2 is a side elevational view with arts of the switching mechanism of Fig. 1 sl iown in section.

Fig. 3 is a plan view on enlarged scale of contact operating mechanism shown in Figs. 1 and 2. V

Fig. 4 is a side elevational view on enlarged scale of a contact and its associated operating mechanism in open circuit position.

Referring to Figs. 1 and 2, the fixed contacts 1 and 2 extending through the switch panel 3, of slate or other suitable insulati material, are adapted to be bridged by the movable contact members 4, carried by arms 5 pivoted at 6 to bracket members 7 secured to and extending from the panel 3. The upper fixed contact 1 is provided with pivoted arching tips 8 of carbon, or the like, adapted to engage the movable arcing tips of similar material 9, mounted in each case upon the end of the spring arm 10 secured between the main contact 4 and its supporting arm 5. As shown most clearly in Fig. 3, the supporting arm 5 is connected by link 11 to a rod or pin 12 whose opposite ends pass through the levers 13, 13, pivoted at 14, 14 to the bracket 7. The actuating arm 15 mounted upon the pivot 16 passing through the outer ends of the bracket members 7 is connected by link 17 to the rod or pin 12, fcrming an undertravelling toggle mecha- IllSIIl.

The springs 18 fastened to brackets 7 through intermediate supports 19 and to extensions of toggle 11 bias the contacts 4 to the open position. Thus far described the switch mechanism corresponds substantially to that of Patent 1,122,430 and per se is not part of the present invention. As indicated in 1g. 1 the units A, B, C and D each comprise a circuit breaking or switching mechamsm, as thus far described, each unit comprising several movable contact members 4 mounted upon a common support 5. The lower ends of the actuating arms 15 of the respective units are connected by a cross or tie bar 20, the respective sets of bolts 21 each clamping the flat plate 22, in which each arm terminates, in flat face to face engagement with the cross bar.

Intermediate its ends, as centrally, the tie bar is rovided with a depending bracket 23 throug which passes the pin 24 to effect connection with the yoke 25 at the upper end of the link 26 whose lower end is connected through a pin 27 to the lever 28 pivoted at 29 to projections of the casing 31 of the electromagnetic closing mechanism which comprises a coil 32 and a movable core member 33, which is connected by means of a link 34 to lever 35 mounted at 29 co-pivotally with lever 28 to which it is' detachably connected by means of a system of latches 36, 3840 and 41, normally'operative to hold the two levers in fixed relation to each other, thus rendering the upward movement of core 33 effective to rotate the arm 28 in clockwise direction to cause downward movement of link 26 and consequent'closure of the switch.

With the movable contacts of all units in open circuit position (Fig. 4) upon energizatlon of the coil 32 by a control switch not shown, the core 33 is drawn inwardly of the coil to move the cross bar 20 connecting the contact actuating arms of the units downwardly to the position indicated in Fig. 2 to effect simultaneous closure of all of the contact elements 4. The position to which lever 35 is moved in effecting full closure of the switch is maintained by engagement with housing supported lug 44 of latch 45 which is pivoted at 47 upon arm 35. There is also included, for actuation upon the occurrence of abnormal current flow, means for tripping the latch system 36, 38-40 and 41 to release the arm 28 from engagement with arm 35 and thus permit the opening of the switch members, independent of latch 45, in response to the stress of the springs 18. The above noted means of latch actuation consist of a horseshoe magnet 48 having pole pieces 49, which structure forms a loop around the conductor or group of conductors 2, an armature 5O pivoted at 50a is adapted in the event of overload, to be drawn into contact with the pole pieces 49 thereby engaging the armature extension 510: with vertical lever 52 pivoted at 53, imparting thereto a counter clockwise movement and thrusting in a right hand direction the link 55 hinged thereto at 54, this movement being transmitted through hinge pin 56 to bell crank lever 57 pivoted to the casing 31 at 58; this bell crank lever thus responding with clockwise movement to upward movement of armature 50; the movement of lever 57 is in turn imparted to sublatch 41 pivoted at 43 upon the arm 28, canssponsive to springs 18 and communicated through link 26 to arm 28 thus imparts to the latch plate 38-40 a turning moment in the clockwise direction to which it is free to respond upon withdrawal of sublatch 41. The resulting movement causes latch 36 to slip out of engagement with latch plate 3840,

allowing the circuit breaker to move to open circuit position, in the course of which movement, projection 56 of arm 28 is brought into engagement with projection 57 of latch 45 thereby moving it, in opposition to spring 46, from engagement with lug 44. Arm 35 actuated by the weight of core 33 now moves counter clockwise as viewed in Fig. 2 until latch 36 reengages with latch plate 3840, the passage of hook portion of 36 over the right hand end of latch plate 3840 having in the meantime caused the rotation of the extension 40 into reengagement with the sublatch 41, and the mechanism is again in position to be closed by the electromagnet in response to excitation thereof.

The circuit breaker indicated having the plurality of units A, B, C and 1) each comprising several contact elements is adapted for continuous heavy duty for'cxample for supplying current to electrlc furnaces which are in continuous operation. The number of units and the number of contact elements in each unit, all of which are connected electrically in parallel, may be increased in numher as desired, to attain a switching mechanism of the desired current carrying capacity. For example, each unit may be constructed to carry 9000 am eres at 600 volts, giving a total capacity 0 the breaker indicated of 36,000 amperes.

From time to time, it is desirable-to clean the contacts to maintain low the resistance introduced by them into the circuit. With switching or circuit breaker mechanisms heretofore utilized, this has not been possible without opening the switch as a whole with consequent interruption of service. This is impractical when continuous supply of current is desired or required, as for example to electrical smelting furnaces which are 0 erated 24 hours a day for long periods of time. To avoid this interruption, a duplicate switching mechanism might be cut in during the cleaning operation but this obviously necessitates the purchase and maintenance of a large, expensive switch only infrequently use In the arrangement described, it is possible to decouple any one of the units A, B, etc., from the common operating member or tie bar 20 and to move the contact elements thereof to open circuit osition for cleaning, repair, replacement or t 1e like without interrupting the flow of current through the remaining units whose position is not disturbed.

The unit A, for example, may be d1sconnected from the remaining units and the common operating system, terminating in the cross bar 20, by removing the pair of bolts 21 which clamp the end 22 of the operating arm of that unit against the tie bar. The angular relation between the contacting faces of tleseelemcnts is such that the arm 15 may swil j counter-clockwise, as viewed in Fig. 2 without obstruction by the cross bar20.

At the conclusion of the cleaning or other operation, the contacts 4 of the unit are returned to their closed circuit position by rotation of the arm 15 in clockwise direction as viewedin Fig. 2. To assist in the manual opening or closing of any switch unit or group of switch units against the tension of the springs 18, there may be provided in each switch unit a socket 63 in a boss 64 projecting from the upper side of the respective arms 15 which is adapted to receive the end of a detachable, auxiliary operating lever 65. With the actuating arm 15 in its closed circuit position, the bolts 21 are replaced and the unit thereby again coupled to the cross bar 20.

In like manner each of the other units may be decoupled and their contact elements cleaned, without interruption of service. The

number of contacts in each unit preferably bears such relation to the total number of contacts, that upon the cutting out of any one unit as described, the additional current carried by the remaining contacts is not excessive, or in any event does not substantially or seriously overload them.

When the operator is at work upon one sec tion of the circuit breaker, opening the remaining sections, either accidentally or automatically as upon the occurrence of overload, should be prevented to avoid injury. To this end, a hook link 60 is provided. This hook may be normally attached to the casing 31 by a conveniently removable pin 61; when out of use the hook link hangs upon this pin in the position shown in dotted outline and indicated by 62. To safely lock the circuit breaker in the closed position, the pin 61 is first withdrawn, the hooked end of member 60 placed around the pin 24 and the opposite end again attached to the casin by replace-.

ment of the pin 61. This 100 ing of the switching mechanism avoids danger to the operator from arcs which might accompany the unex ected movement of the switch to open position and also from the possibility of being struck by moving parts of the appli ance. At the conclusion of the cleaning 0 eration the pin 61 is withdrawn, and the hook. ing link 60 unhooked from the pin 24. The

position, one of the switching units cannot be decoupled and moved independently of the others to closed circuit position. Clockwise rotation of the arm 15 with respect to the cross bar 20 is prevented as the radial length of the arm is greater at its trailing edge than at its leading edge, the bar 20 itself obstructing independent movement of the de-coupled arm. Further, if the auxiliary lever 65 is inserted in the socket 63 of a de-coupled unit, while the bar 20 is in its upper or open circuit position, obviously the lever 65, assuming that the arm 15 could swing free of the bar 20, could not be swung downwardly without hitting the cross bar 20.

It will be understood that my invention is applicable to switches, with or without electro-responsive tripping means, which are directly manually operable instead of through an intermediate agency, electricity, for example, as in the mechanism above specifically described.

What I claim is:

1. Switch mechanism including a plurality of movable contract elements collectively comprising one pole of the switch, stationary contact structure, means mechanically connecting said movable contact elements for effecting simultaneous movement thereof into engagement with said stationary contact structure to complete a circuit, and means for permitting the disconnection of a selected contact element from said structure and movement thereof. to open circuit position without interruption of flow of current through said switch.

2. Switch mechanism including a plurality of movable contact elements collectively comprising one pole of the switch, structure mechanically coupling said elements for simultaneous movement thereof to a circuit-controlling position, and means for permitting selective decoupling of said elements from said structure for movement of the selected element to another circuit-controlling position independent of said structure and other of said elements.

3. Switch mechanism having a plurality of movable contact elements collectively comprising one pole of the switch, structure mechanically coupling said elements for simultaneous movement to a circuit-controlling position, mechanism for retaining said elements in said position, and means for permitting selective decoupling of said elements from said structure and release from said restraining means for movement of the selected contact element to another circuit controlling position.

4. Switch mechanism havin a plurality of movable contact elements col ectively comprising one pole of the switch, structure mechanically coupling said elements for simultaneous movement thereof to a circuit-controlling position, locking mechanism preventing movement of said structure with said elements in said circuit-controlling position, and means for permitting disconnection of a selected contact element from I said locked structure for movement to another circuitcontrolling position.

5. Switch mechanism having a plurality of movable contact elements collectively comprising one pole of the switch, structure mechanically coupling said elements for simultaneous movement thereof to a circuit-controlling position, mechanism for retaining said elements in said position, locking mecha- .nism preventing movement of said structure with said elements in said circuit-controlling position, and means for permitting disconnection of a selected contact element from said lock structure and release from said retaining mechanism for movement to another circuit-controlling position.

6. Switch mechanism having a plurality of units each including a contact element and an actuating lever said'plurality of .units comrising one pole of the switch, an operating Ear connecting said levers for simultaneous movement of said contact elements to closedcircuit position, and means for permitting disconnection between said bar and the actuating lever of a selected unit for movement of the contact element thereof to open-circuit position.

7. Switch mechanism comprising a plurality of movable contact elements, actuating arms therefor, an operating member, means connecting said arms individually to said a member for simultaneous movement of said contact elements, and structure permitting upon disconnection of one of said arms from said member movement in one direction only of said one of said arms.

8. Switch mechanism comprising a'plurality of movable contact elements, actuating arms therefor, an operating system comprising a movable member, means connecting said arms individually to said member for simultaneous movement of said contact elements, the relation between the arms and member being such that disconnection of an arm permits movement in one direction only from said member, and means for preventing movement of .said system when sald member is in a position corresponding to closed circuit position of the actuating arms connected thereto.

9. Switch mechanism comprising a plurality of movable contact elements, co-axially pivoted actuating arms having inclined ends,

a tie-bar, and means holding the inclined ends of said arms individually 1n face to face engagement with said bar, the disconnection of an individual arm ermitting its movement in one direction on y.

10. Switch mechanism comprising a plurality of movable contact elements, actuating arms therefor, toggles connecting said actuating arms to respective contact elements, latch structure for holding said to gles in extended position, an operating mein r coupling said actuating arms for simultaneous movement of said contacts to closed circuit position and extending said toggles, auxiliary means cooperating with said member for olding said contacts in closed position independently of said latch structure, and means for decoupling a selected actuating arm from said operating member to permit movement of the associated contact element to open circuit position. I

11. Switch mechanism comprising a plurality of movable contact elements, actuating arms therefor, latch structure for holding said elements in closed circuit osition, electro-responsive means for releasing said latch structure under abnormalcircuit conditions, an operating member coupling said arms for simultaneous movement, means for disabling said electro-responsive means to prevent release of said latch structure in response to circuit conditions, and means for de-coupling a selected actuating arm from said operating member when said switch mechanism is in closed circuit position and said disabling means effective, to permit movement solely of the corresponding contact element to open circuit position. v

12. A single pole circuit breaker comprising a plurality of movable brushes adapted to engage the fixed contact elements of the circuit breaker and electricall connected in parallel when the circuit brea er is in closed position, structure mechanically connecting said movable brushes. for effecting simultaneous movement thereof to open or closed position, means operable when. the circuit breaker-is in closed position for mechanically disconnecting at will any of said brushes from said structure for independent movement to an open position, and means for preventing movement of any such disconnected brush to closed position when the circuit breaker is in open position.

13. Switch mechanism comprising relatively fixed contact structure, a plurality of movable contact elements collectively comprising one pole of the switch, structure mechanically connecting said movable contact elements for effecting simultaneous movement thereof into engagement with said fixed contact structure, and means operable when the switch is in closed position for permitting mechanical disconnection from said connecting structure of any of said movable contact elements for independent movement to open position.

14. Switch mechanism including a plurality of units collectively comprismg one pole of the switch, each of said units including a contact element and an actuating arm, an operating bar, and means individually connecting said arms to said bar for simultaneous movement of said contact elements to closed circuit position, the angular relation between the cooperating faces of the bar and said arms being such that upon disconnection from the bar of a selected arm the latter is independently movable to open circuit position.

15. Switch mechanism including a plurality of movable contact elements collectively comprising one pole of the switch, actuating levers therefor, an o crating mem ber connecting said levers to e ect simultaneous movement of said contact elements to and away from closed circuit position, and means permitting disconnection of the bar from a selected actuating lever to permit independent operation of the corresponding contact away from and toward closed circuit position.

16. A circuit breaker comprising fixed contact structure, a group of movable contact members in circuit with one pole of the circuit breaker, saidmembers positioned adjacent each other and adapted to engage said fixed contact structure when the circuit breaker is in closed position, means mechanically connecting said movable contact members for efl'ecting simultaneous movement thereof to open or closed position, and means operable when the contact members are in closed position for mechanically disconnecting at will any of said members for independent movement to open position.

17. A circuit breaker comprising contact members, a group of movable bridge members comprising one pole of the circuit breaker and adapted to engage said contact members to close a circuit between them when the circuit breaker is in closed position, a member mechanically connecting said movable bridge members for eifecting simultaneous movement thereof to open or closed position, and means operable when the circuit breaker is in closed position for mechanically disconnecting at will any of said bridge members for independent movement to open position.

18. A circuit breaker comprising a supporting panel, contact structure mounted thereon, a group of movable contact units in circuit with one pole of the circuit breaker, said movable contact units having main contacts and shunt contacts connected respectively in parallel with each other when the circuit breaker is in closed position, operating means common to said movable contact units for effecting simultaneous movement thereof into engagement with said contact structure, and means operable when the circuit breaker is in closed position for disconnecting at will from said operatin means any of said movable un1ts for in ependent movement to open position.

19 A circuit breaker comprising a supporting panel, a contact structure mounted thereon, a group of movable contact units in circuit with one pole of the circuit breaker, said movable contact units having main contacts and arcing contacts connected respectively in parallel with each other when the circuit breaker is in closed position, an operating member mechanically connecting said movable units for efiecting simultaneous movement thereof into engagement with said contact structure, and means operable when the circuit breaker is in closed position for disconnecting at will from said operating member any of said movable units for independent movement to open position.

20. An automatic circuit breaker comprising a plurality of movable contact elements, individual undertravelling actuating toggles therefor, an operating member coupled to said. toggles for simultaneous movement of said contact elements to closed circuit position, latch structure common to said toggles for holding them extended, and means operable when the circuit breaker is in closed position for decoupling from said operating member any selected toggle to permit movement of the associated contact element to open circuit position.

21. An automatic circuit breaker compris ing a plurality of movable contact elements, individual undertravelling actuating toggles therefor, means coacting individually with said toggles biasing the same toward collapsed position, an operating member coupled to said toggles for simultaneous movement of said contact elements to closed circuit position, latch means common to said toggles for holding them extended, and means operable when the circuit breaker is in closed position for mechanically disconnecting from said operating member any selected toggle to permit movement of the associated contact element to open circuit position.

22. An automatic circuit breaker comprising a plurality of movablecontact elements, an undertravelling toggle for actuating each of said contact elements, an operating member common to said toggles, means for detachably mechanically connecting a pivoted link of each of said toggles to said operating member, and latch structure common to said toggles for holding them extended, the pivoted link of any selected toggle, upon disconnection thereof from said operating member while said circuit breaker is in closed position, rotating away from said operatin member to permit movement of the associated contact element to open circuit position.

23. Switch mechanism comprising a 111'- rality of movable contact elements co ectivel comprising one pole of the switch, indivi ual actuating members for said contact elements, operating structure mechanically coupling, sald. actuating members for eflecting simultaneous movement of the contact elements to closed circuit osition, means permitting selective de-coup ing from said operatin structure of said actuating members for independent movement of the associated contact elements to open circuit position, said actuating members having means for detachable engagement therewith of a manually operable device for effecting said independent movement of the contact elements.

24. An automatic circuit breaker comprismg a plurality of movable contact elements co lectively comprising one pole of the circuit breaker, individual actuating members for said contact elements, operating structure mechanically coupling said actuating members for effecting simultaneous movement of the contact elements to closed circuit position, means permitting selective de-coupling from said operating structure of said actuatin contact elements to open circuit position, an means operable at will for holding the operating structure in closed circuit position to prevent opening of the circuit breaker when one of said actuating members is decoupled from said operating structure.

25. An automatic circuit breaker comprising a plurality of movable contact elements collectively comprising one ole of the circuit breaker, individual actuating members for said contact elements, operating structure mechanically coupling said actuating members for effecting simultaneousmovement of the contact elements to open or closed circuit position, latch structure for holding said operating structure in closed circuit position under normal operating conditions, and means operable at will for holding the operating structure in closed circuit position to prevent opening of the oircuit breaker when one of said actuating members is decoupled from said operating structure.

WILLIAM M. SCOTT, JR. 

